diff --git a/xarray/computation/nanops.py b/xarray/computation/nanops.py
index a28078540bb..862487db996 100644
--- a/xarray/computation/nanops.py
+++ b/xarray/computation/nanops.py
@@ -107,10 +107,6 @@ def _nanmean_ddof_object(ddof, value, axis=None, dtype=None, **kwargs):
     """In house nanmean. ddof argument will be used in _nanvar method"""
     valid_count = count(value, axis=axis)
     value = fillna(value, 0)
-    # As dtype inference is impossible for object dtype, we assume float
-    # https://github.com/dask/dask/issues/3162
-    if dtype is None and value.dtype.kind == "O":
-        dtype = float
 
     data = np.sum(value, axis=axis, dtype=dtype, **kwargs)
     data = data / (valid_count - ddof)